But before dealing with this new development of the latter half of 1915 it is necessary to consider certain general aspects of the deadlock war.  It is manifest that the Germans hoped to secure an effective victory in this war before they ran up against Bloch.  But reckoning with Bloch, as they certainly did, they hoped that even in the event of the war getting to earth, it would still be possible to produce novelties that would sufficiently neutralise Bloch to secure a victorious peace.  With unexpectedly powerful artillery suddenly concentrated, with high explosives, with asphyxiating gas, with a well-organised system of grenade throwing and mining, with attacks of flaming gas, and above all with a vast munition-making plant to keep them going, they had a very reasonable chance of hacking their way through.

Against these prepared novelties the Allies have had to improvise, and on the whole the improvisation has kept pace with the demands made upon it.  They have brought their military science up to date, and to-day the disparity in science and equipment between the antagonists has greatly diminished.  There has been no escaping Bloch after all, and the deadlock, if no sudden peace occurs, can end now in only one thing, the exhaustion in various degrees of all the combatants and the succumbing of the most exhausted.  The idea of a conclusive end of the traditional pattern to this war, of a triumphal entry into London, Paris, Berlin or Moscow, is to be dismissed altogether from our calculations.  The end of this war will be a matter of negotiation between practically immobilised and extremely shattered antagonists.

There is, of course, one aspect of the Bloch deadlock that the Germans at least have contemplated.  If it is not possible to get through or round, it may still be possible to get over.  There is the air path.

This idea has certainly taken hold of the French mind, but France has been too busy and is temperamentally too economical to risk large expenditures upon what is necessarily an experiment.  The British are too conservative and sceptical to be the pioneers in any such enterprise.  The Russians have been too poor in the necessary resources of mechanics and material.

The Germans alone have made any sustained attempt to strike through the air at their enemies beyond the war zone.  Their Zeppelin raids upon England have shown a steadily increasing efficiency, and it is highly probable that they will be repeated on a much larger scale before the war is over.  Quite possibly, too, the Germans are developing an accessory force of large aeroplanes to co-operate in such an attack.  The long coasts of Britain, the impossibility of their being fully equipped throughout their extent, except at a prohibitive cost of men and material, to resist air invaders, exposes the whole length of the island to considerable risk and annoyance from such an expedition.

It is doubtful, though, if the utmost damage an air raid is likely to inflict upon England would count materially in the exhaustion process, and the moral effect of these raids has been, and will be, to stiffen the British resolution to fight this war through to the conclusive ending of any such possibilities.